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Applied Optics

Applied Optics


  • Editor: Joseph N. Mait
  • Vol. 48, Iss. 30 — Oct. 20, 2009
  • pp: 5802–5810

Terminal reflections in fiber-optic image guides

Pierre M. Lane  »View Author Affiliations

Applied Optics, Vol. 48, Issue 30, pp. 5802-5810 (2009)

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Fibered image guides for confocal reflectance endomicroscopy suffer from Fresnel reflections at the fiber terminals, which can limit signal-to-noise ratio in these systems. A model that describes these terminal reflections is presented to better understand how they can be managed most effectively. An expression for the refractive index of termination that minimizes the reflection as a function of the fiber’s normalized frequency is derived for step-index fibers, while a graphical solution is presented for graded-index fibers. The model predicts that terminal reflections from graded-index fibers are more sensitive to variations in fiber size and changes in wavelength than step-index fibers. A method is also presented to measure the refractive index that allows one to minimize the terminal reflections in an image guide. The technique uses the inherent mode coupling of the fibers in the image guide, allowing the isolation and measurement of reflections from only one end of the fiber. An achievable minimum backreflection of 36 dB was measured at 635 nm in a commercial image guide with 30,000 fibers.

© 2009 Optical Society of America

OCIS Codes
(060.2270) Fiber optics and optical communications : Fiber characterization
(060.2350) Fiber optics and optical communications : Fiber optics imaging
(110.2350) Imaging systems : Fiber optics imaging
(120.3890) Instrumentation, measurement, and metrology : Medical optics instrumentation
(170.1790) Medical optics and biotechnology : Confocal microscopy
(170.2150) Medical optics and biotechnology : Endoscopic imaging

ToC Category:
Fiber Optics and Optical Communications

Original Manuscript: June 15, 2009
Revised Manuscript: September 25, 2009
Manuscript Accepted: September 25, 2009
Published: October 16, 2009

Virtual Issues
Vol. 4, Iss. 12 Virtual Journal for Biomedical Optics

Pierre M. Lane, "Terminal reflections in fiber-optic image guides," Appl. Opt. 48, 5802-5810 (2009)

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  1. A. F. Gmitro and D. Aziz, “Confocal microscopy through a fiberoptic imaging bundle,” Opt. Lett. 18, 565-567 (1993). [CrossRef]
  2. C. MacAulay, P. Lane, and R. Richards-Kortum, “In vivo pathology: microendoscopy as a new endoscopic imaging modality,” Gastrointest. Endosc. Clin. N. Am. 14, 595-620(2004). [CrossRef]
  3. K. Sokolov, K. B. Sung, T. Collier, A. Clark, D. Arifler, A. Lacy, M. Descour, and R. Richards-Kortum, “Endoscopic microscopy,” Dis. Markers 18, 269-291 (2002).
  4. B. A. Flusberg, E. D. Cocker, W. Piyawattanametha, J. C. Jung, E. L. M. Cheung, and M. J. Schnitzer, “Fiber-optic fluorescence imaging,” Nat. Methods 2, 941-950 (2005). [CrossRef]
  5. Y. S. Sabharwal, A. R. Rouse, L. Donaldson, M. F. Hopkins, and A. F. Gmitro, “Slit-scanning confocal microendoscope for high-resolution in vivo imaging,” Appl. Opt. 38, 7133-7144(1999). [CrossRef]
  6. A. K. Dunn, C. Smithpeter, A. J. Welch, and R. Richards-Kortum, “Sources of contrast in confocal reflectance imaging,” Appl. Opt. 35, 3441-3446 (1996). [CrossRef]
  7. M. Rajadhyaksha, M. Grossman, D. Esterowitz, R. H. Webb, and R. R. Anderson, “In-Vivo confocal scanning laser microscopy of human skin--melanin provides strong contrast,” J. Invest. Dermatol. 104, 946-952 (1995). [CrossRef]
  8. C. Smithpeter, A. Duan, R. Drezek, T. Collier, and R. Richards-Kortum, “Near real time confocal microscopy of cultured amelanotic cells: sources of signal, contrast agents and limits of contrast,” J Biomed. Opt. 3, 429-436 (1998). [CrossRef]
  9. R. Drezek, A. Dunn, and R. Richards-Kortum, “Light scattering from cells: finite-difference time-domain simulations and goniometric measurements,” Appl. Opt. 38, 3651-3661(1999). [CrossRef]
  10. I. Pavlova, K. Sokolov, R. Drezek, A. Malpica, M. Follen, and R. Richards-Kortum, “Microanatomical and biochemical origins of normal and precancerous cervical autofluorescence using laser-scanning fluorescence confocal microscopy,” Photochem. Photobiol. 77, 550-555 (2003). [CrossRef]
  11. E. R. Hsu, A. M. Gillenwater, M. Q. Hasan, M. D. Williams, A. K. El-Naggar, and R. R. Richards-Kortum, “Real-time detection of epidermal growth factor receptor expression in fresh oral cavity biopsies using a molecular-specific contrast agent,” Int. J. Cancer 118, 3062-3071 (2006). [CrossRef]
  12. T. Collier, A. Lacy, R. Richards-Kortum, A. Malpica, and M. Follen, “Near real-time confocal microscopy of amelanotic tissue: detection of dysplasia in ex vivo cervical tissue,” Acad. Radiol. 9, 504-512 (2002). [CrossRef]
  13. T. Collier, M. Guillaud, M. Follen, A. Malpica, and R. Richards-Kortum, “Real-time reflectance confocal microscopy: comparison of two-dimensional images and three-dimensional image stacks for detection of cervical precancer,” J. Biomed. Opt. 12, 024021 (2007). [CrossRef]
  14. A. L. Clark, A. M. Gillenwater, T. G. Collier, R. Alizadeh-Naderi, A. K. El-Naggar, and R. R. Richards-Kortum, “Confocal microscopy for real-time detection of oral cavity neoplasia,” Clin. Cancer Res. 9, 4714-4721 (2003).
  15. J. A. Udovich, A. R. Rouse, A. Tanbakuchi, M. A. Brewer, R. Sampliner, and A. F. Gmitro, “Confocal microendoscope for use in a clinical setting,” Proc. SPIE 6432, H64320H(2007).
  16. P. M. Lane, S. Lam, A. McWilliams, J. C. Leriche, M. W. Anderson, and C. E. MacAulay, “Confocal fluorescence microendoscopy of bronchial epithelium,” J Biomed. Opt. 14, 024008 (2009). [CrossRef]
  17. K. B. Sung, C. N. Liang, M. Descour, T. Collier, M. Follen, and R. Richards-Kortum, “Fiber-optic confocal reflectance microscope with miniature objective for in vivo imaging of human tissues,” IEEE Trans. Biomed. Eng. 49, 1168-1172 (2002). [CrossRef]
  18. P. M. Lane, A. L. P. Dlugan, R. Richards-Kortum, and C. E. MacAulay, “Fiber-optic confocal microscopy using a spatial light modulator,” Opt. Lett. 25, 1780-1782 (2000). [CrossRef]
  19. K. B. Sung, C. Liang, M. Descour, T. Collier, M. Follen, A. Malpica, and R. Richards-Kortum, “Near real time in vivo fibre optic confocal microscopy: subcellular structure resolved,” J. Microsc. 208, 75-75 (2002). [CrossRef]
  20. A. W. Snyder and J. D. Love, Optical Waveguide Theory (Chapman and Hall, 1983).
  21. K. L. Reichenbach and C. Xu, “Numerical analysis of light propagation in image fibers or coherent fiber bundles,” Opt. Express 15, 2151-2165 (2007). [CrossRef]
  22. X. P. Chen, K. L. Reichenbach, and C. Xu, “Experimental and theoretical analysis of core-to-core coupling on fiber bundle imaging,” Opt. Express 16, 21598-21607 (2008). [CrossRef]
  23. R. Conde, C. Depeursinge, B. Gisin, N. Gisin, and B. Groebli, “Refractive index profile and geometry measurements in multicore fibres,” J. Opt. A Pure Appl. Opt. 5, 269-274 (1996).
  24. P. Lane, “Reflection-contrast limit of fiber-optic image guides,” J Biomed. Opt. (to be published).
  25. N. Kuwamura, Sumitomo Electric USA, Inc. (personal communication, 2009).
  26. J. A. Udovich, N. D. Kirkpatrick, A. Kano, A. Tanbakuchi, U. Utzinger, and A. F. Gmitro, “Spectral background and transmission characteristics of fiber optic imaging bundles,” Appl. Opt. 47, 4560-4568 (2008). [CrossRef]
  27. Y. W. Ma and L. Huang, “The crosstalk study of order-packed flexible image bundles,” Proc. SPIE 3552, 232-237 (1998). [CrossRef]

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